Traditionally, tubular fluorescent lighting products which are utilized to provide a continuous uninterrupted line of light for both curved and straight lighting applications can be separated into three categories:
1). Fixtures and systems which use standardized straight tubular lamps in novel ways (either by overlapping, staggering or angling) to both navigate curved and straight architectural details, and overcome the problems created by the non-illuminated lamp end(s).
2). Fixtures and systems which utilize straight tubular lamps (e.g., butt-ended cold cathode fluorescent lamps) which, through their unique construction, do not exhibit the typical non-illuminated lamp end(s), thus providing continuous even illumination from one end of the lamp body to the other, allowing end-to-end installation. These straight lengths are configured in various ways, e.g., angled or overlapped to conform to curved and/or straight architectural requirements.
3). Fixtures and systems which utilize the uniquely constructed lamps described in the paragraph above in which the lamps may also be made as custom or standardized straight, bent or custom-curved elements that can conform to almost any architectural or design requirement.
Examples of systems which utilize standardized straight tubular lamps and fixtures described in category #1 would include a simple staggered fluorescent fixture, such as the one currently manufactured by Bartco. The non-illuminated ends of the lamp are compensated by overlapping the tubular lamp body. This type of system could be used for straight or very gently curved applications, the length of the standardized lamp determining the minimum radius on which they can be installed. Systems which utilize a staggered lamp configuration suffer from overly bright areas of illumination where the lamps overlap, and can produce a pattern of alternating brightness when the fixtures are used in an indirect application. Additionally, because the lamps are configured side-by-side, and not in a true linear array, even the untrained eye can see that the surfaces closest to each lamp are more brightly illuminated than those even slightly farther away. That is, where tubular lamps are staggered side by side, the cove will exhibit uneven light distribution. The lamps closest to the back of the cove will create a lower-brightness light pattern at the front of the cove, and lamps closest to the front of the cove will produce a lower-brightness light pattern at the back of the cove.
Some manufacturers utilize smaller biax or compact-fluorescent lamps in an overlapping or non-overlapping placed array. In the case of this type of lamp, only one end of the lamp is not illuminated. This type of lamp is essentially a “U” shaped tubular fluorescent that has an exceedingly small area in which the lamp returns on itself, giving it the appearance of twin lamps, side by side. To conceal the non-illuminated portion of the lamp that accommodates the lamp base, these lamps can be mounted in an overlapping fashion in which the illuminated end of one lamp conceals the non-illuminated end of the adjacent lamp. These lamps can be installed on fixtures that are either straight, semi-flexible, or segmented with a swiveling feature, allowing the fixture itself to be field-curved to the desired shape. Examples of this type of fixture are manufactured by Belfer, Inc. Each lamp is attached either at a tangent to a semi-flexible curvable element or to a curvable, swiveling, segmented element. The curvable elements are designed to accommodate a plurality of straight, small lamps and usually contain the power supplies which operate the lamps. The disadvantages of the above-referenced system are that the non-overlapping lamp configuration exhibits dark spots and shadowing between the lamps, and the overlapping system is not as maximally efficient due to the relatively high lamp quantities and corresponding high wattage densities required by the overlapping feature.
Examples of systems that utilize straight tubular lamps and fixtures described in category #2 would include a cold cathode fluorescent lighting system shown in U.S. Pat. No. 6,454,431, incorporated herein by reference. There, a lighting system having self-contained aluminum-extrusion fixtures accept a variety of standardized lamp lengths. The standardization of the fixture and lamp sizes minimizes manufacturing and project design expenses. The lamps are uniquely constructed to provide uniform illumination from one end of the lamp to the other. The lamp base and cathode that would normally create a non-illuminated space at each end of the lamp has been moved behind and underneath the lamp, allowing continuous illumination at each end of the lamp body. The fixtures, and correspondingly, the lamps, may be arranged end-to-end, producing a continuous shadow and gap-free line of light. To transition slight curvatures, fixtures can be installed at angles to one another. Depending upon the radius required and the most minimal lamp length, a limited variety of very large gentle radii can be accommodated. Smaller radii and complex curvilinear shapes cannot be accommodated. This is an inherent disadvantage of the system. It is not offered as a curved or bent fixture that could accommodate curved or bent lamps needed for more complex and curved architectural requirements.
Another example of a fixture of this type is the Seamlessline fixture, manufactured by Nippo Inc. This fixture utilizes a special standardized fluorescent lamp, which is manufactured to provide complete illumination of the tubular lamp body. Again, lamps can be installed to transition gradual curves depending upon the radius required and the most minimal lamp length. The lamp utilized in this type of fixture is of the “hot cathode” design. The lamp life is typically 12,000 hours, far less than the 50,000 hour cold cathode fluorescent lamp. This system is offered in straight lengths only.
Examples of systems that utilize tubular lamps and fixtures described in category #3 would include a cold cathode fluorescent lighting system manufactured by Cathode Lighting Systems. This is a component-based system which is comprised of custom-made lamps and lamp components that can either be field assembled or partially factory assembled utilizing standard electrical conduits, conduit connectors and wiring. The lamps can be fabricated to nearly any shape as desired, either straight, curved or bent. Each of the components is shipped separately to the installation site where a contractor installs the conduit and wiring between the lampholder and ballasts. These systems are almost always field-assembled.
A disadvantage of the system is that it is costly to install, and must be field-assembled from a variety of components (some provided by the lighting manufacturer, and some provided by the installing contractor). The lampholders retain and electrically connect the ends of adjacent lamps to the lamp ballast(s). This assures the spacing between lamp ends is always maintained at the proper dimension. On the other hand, because the lampholders retain the ends of adjacent lamps, there is little room for adjustment of the system if adjustment is required. The system is essentially built to a fixed dimension, and each lamp dimension and placement is dependent upon the adjacent segment. Any readjustment of lampholder positioning or spacing of an individual segment would either break the lamp(s), or require a redesign of the lamp(s) or system. Because field conditions vary, the ability to reposition the system and manipulate the spacing of the lamps ends would be advantageous.
Another cold cathode lighting system has been suggested where a continuous channel which contains the power supply and wiring for the lamp is custom-built to the exact shape of the lamp. An example of this system is manufactured by Neotek, Inc. The channel is assembled using a combination of extruded shapes and/or flat metal elements that can be factory-fabricated to form straight, curved or bent elements, to follow the shape of the custom-made lamp. These fixtures do not contain lampholders, which in almost all tubular light fixtures, connect the lamp (via a lamp base) to the power supply. Lamp base(s) and lampholder(s) type fixtures allow easy insertion and removal of a lamp, without any disassembly of the fixture. Rather, in the Neotek fixture, lamps are glued to the top portion of the snap-on channel and are connected to the power supply via a flexible conductor. The disadvantages of this product include the following:
A). A uniquely shaped or dimensioned custom channel must be factory-built for each unique lamp shape, requiring substantial labor, and if the fixture is dimensionally incorrect, it cannot be field-adjusted, it must be remade, along with the lamp.
B). Because the lamp is glued to the removable top portion of the channel and does not utilize traditional lamp bases and lampholders, if a lamp needs replacement, an entire new glued-together top channel and lamp assembly must be fabricated.
C). There are some limitations as to how small a radius or acute angle this type of (or any type of metallic channel-based) fixture can be manufactured to duplicate. These limitations are based on the physical properties of the material, the overall size of the channel and the limitations of the manufacturing techniques.
D). If field conditions dictate that a few fixtures in a predetermined array length require more separation between fixtures, these open-ended fixtures must be enclosed at each end, and like almost all linear fixtures (e.g. the fixture described in the '431 patent, which are always enclosed at each end, and allow concealed wiring from one fixture to the next, via standard electrical knockouts and standardized electrical fittings) will require external rerouting of the internal wiring, via electrical conduit, from one fixture to the next.
There is a desire for a fixture that can accommodate virtually any size or shape tubular lamp, essentially a “one size fits all” fixture. Also desired is an uncomplicated method of installing the desired fixture, such that a contractor can install the fixtures, install the lamps within the fixtures, and electrically connect the fixtures to each other, and electrical power, without any disassembly of the fixture whatsoever. Also desired is a fixture that can be field-adjusted or spaced at a variety of distances or orientations from each adjacent fixture without the requirement of building additional conduits or raceways to electrically connect one fixture to the next.